1. Field of the Invention
The present invention relates to bulk material handling. More specifically, the invention relates to the transportation, storage and dispensing of a multitude of dry bulk products such as gravel, sand, and mine minerals.
2. Description of the Related Art
Demurrage refers to the charges paid to a transporter for extra use of the transporting equipment as a result of wait time. Demurrage is one of the primary cost drivers in shipping material from a source (e.g., a quarry, construction site, industrial site, or agricultural site), and may apply at either end of the haul.
For example, a typical source may operate for a limited time (e.g., twelve hours) each day. In the event a particularly large order of material is to be hauled from the source on a given day, trucks may be lined up waiting to be loaded with material because the source cannot operate fast enough to eliminate wait time. This results in less product movement for the source and additional demurrage charges to the customer for the trucks that are filled later in the queue. In addition, the current practice in loading trucks may also include the trucks entering into the quarry to be loaded. In doing so, the trucks get really messy—the degree to which may depend on the weather—and end up removing dirt and mud from the quarry and tracking same all over the roads requiring substantial clean-up costs.
The same bottleneck may occur with material delivery. If a large number of trucks arrive within a short time period at the delivery site for the material, the trucks that arrived last may be forced to wait while the earlier trucks unload their material first. Typically, these trucks are of the belly-dump or end-dump variety, which have relatively lengthy unloading times. Thus, the receiving party may incur demurrage charges associated with the later arriving trucks because of the amount of time it takes for the earlier arrived trucks to dump their load.
Take, for example, gravel or base material to be used for a highway foundation. This means contractors from around the country use material from a limited number of quarries, resulting in large numbers of trucks arriving at the quarries to accept loads for delivery throughout the United States. If the quarries cannot load the material quickly enough into the waiting trucks, someone—maybe the quarry, maybe the customer—incurs demurrage charges.
Similarly, if a truck delivers bulk materials to the construction site but cannot unload immediately on arrival, the contractor is charged demurrage for waiting. In fact, it is not uncommon at a construction site for a number of trucks to be waiting in line to be unloaded, for which the contractor is being charged for demurrage. It is important that as soon as the bulk materials are delivered to the construction site, they can be immediately unloaded to minimize demurrage charges.